Lazarus

Programming => LCL => Topic started by: ϻαϻɾΣɀО on June 01, 2019, 10:02:44 pm

Title: TCustomFreeTypeFontCollection Enumerator
Post by: ϻαϻɾΣɀО on June 01, 2019, 10:02:44 pm

Hi Guys,
For the TCustomFreeTypeFontCollection there are two enumerators:

Code: Pascal  [Select][+][-]

1.    
2.     function FontFileEnumerator: IFreeTypeFontEnumerator; virtual; abstract;
3.     function FamilyEnumerator: IFreeTypeFamilyEnumerator; virtual; abstract;
4.  

But I cannot figure out how to use them!
Can someone help me?

Title: Re: TCustomFreeTypeFontCollection Enumerator
Post by: ϻαϻɾΣɀО on June 01, 2019, 10:51:04 pm

I found something like this and it works:

Code: Pascal  [Select][+][-]

1. function GetFontFamilies: TStringList;
2. var
3.   enm: IFreeTypeFamilyEnumerator;
4. begin
5.     Result := TStringList.Create;
6.     enm := FontCollection.FamilyEnumerator;
7.     while enm.MoveNext do
8.       Result.Add(enm.Current.FamilyName);
9. end;
10.  

any beter suggestion?
I mean something like

Code: Pascal  [Select][+][-]

1.  for family in FontCollection do...

Title: Re: TCustomFreeTypeFontCollection Enumerator
Post by: jamie on June 02, 2019, 12:27:28 am

Yes you fingered it out  :)

You can even write your enumerators in your classes that you make, all you need is the GetEnumerator function

That allows the loop counter using "IN" to function.


http://wiki.freepascal.org/for-in_loop

Title: Re: TCustomFreeTypeFontCollection Enumerator
Post by: devEric69 on June 02, 2019, 09:53:12 am

Nice insight.
And just as a reminder, for those who are "paranoid" and want to free the memory by themselves, once the interface is used (without letting the interfaces's _refcount do its job as a "garbage collector"), you must assign the interface's variable with nil to free it, like:

Code: Pascal  [Select][+][-]

1. GetFontFamilies function: TStringList;
2. begin
3.         .../...
4.         enm:= nil;  //free the intrfc expressly
5. end;